Thursday 13 August 2015

Ever Experienced a Chinese Gybe? This frightening Experience Can be Avoided! Here are some tips to help.

You Know the feeling,  Its a beautiful day to be on the water..  Sun is shining, wind is climbing...  Maybe you should think about reefing, but there is that boat you have been battling for the last hour and you don't want to lose a knot or two for the time it takes to put in the reef to control the heel...  Things are starting to get exciting but on the helm you can feel the boat taking control away from you.  Anyone on the boat who has experienced a "Chinese Gybe" is feeling the pressure as you start to fight the roll to windward.  

 
That Leeward point to round is right on the edge and you are pushing it as you don't want to put in a time consuming (and risky)gybe.  All it takes is a slight rise in pressure and you know it instantly as the boat heels to windward just a touch more and you are now poised right on the edge of what you have experienced before and hoped not to again.  Split seconds from the infamous Chinese Gybe or aptly named, "Crash Gybe" or "Death Roll". 
 
What’s the cause?

In order for the death roll to start you normally have a combination of all or most of the below:
  • Sailing dead downwind or very close to it.
  • Mainsail hasn’t got enough vang on, causing it to twist a lot, hence creating a sideway force.
  • Spinnaker too loosely sheeted and not “strapped down”, allowing it to sway from one side to the other
  • Boat (slightly) over-powered for the wind it’s sailing in
  • Often gusty conditions
  • Waves can also help trigger the death roll movements
 
 
1.  Move as much weight aft!
 
 The stability of the boat can be increased by moving crew weight aft.  The bow is unstable and given floatation due to the narrow design.  Altho, you must be careful about making this move too quickly as you can drag your stern.  Not really too much of a concern unless you are pitted in a tight race.  Each boat is different and so you will learn from experience with your vessel, when the right time to shift weight has been reached.   A competent and experienced crew knows in a time like this, coming up on your mark, that it is time to be on attention and ready to stay low and use their body weight to stabilize the boat.
 
2. Control mainsail twist
 
The mainsheet will probably be all the way out, but putting on more vang will help stop the boat from rolling. Make sure the cunningham is all the way off as both these have control over the leech.
If the mainsail is too open at the top then the side forces are working against you (ie to windward). Pull it in when the boat rolls to windward and let it out again when upright. Trimming the two sails in unison will have a good effect on keeping the boat tracking straight.

 
3. Spinnaker Control
 
 
If you are at this point flying a spinnaker, your trimmer will want to run the pole forward to create a more stable approach.  Maybe halfway between the head stay and the shrouds  This helps as the spinnaker is pushing a little to leeward rather than hard forward, which shifts the boat balance forward onto the narrow bow.
 
Over trim the Spinny slightly and bring the tweaker on HARD!   This will help balance the boat. 
Heeling to Windward = Wind the sheet on!
Heeling to Leeward = Ease the Sheet!
 
 

 
PW 5 tips Diagram

4. Smoke the brace (dump the guy)
 
 
The most effective tool for saving these wipeouts is to ‘smoke’ the guy to the headstay. It might create enough leeward side force to bring the boat back onto its feet, but the trimmer needs to be very aware. Good communication between helm and trimmer is critical as you don’t want to be winding the guy back when release was never needed!
If the worst does happen then make sure heads are down and everyone is hanging on and don’t ease the spinnaker sheets. If recovery requires dropping the spinnaker then keeping it close to the boat makes life a lot easier.
 
5. Emphasis on steering
 
 
For the helmsman it can be quite a good workout! Make sure you are in a good body position so that you can push and pull the tiller without having to adjust your stance each time as a split second delay could be a death knell.
If you are trying to run deep the key thing is to watch the spinnaker. If you allow it to get too far to one side of the boat it can be difficult to get it back. ‘Keep the boat under the spinnaker’ is obvious advice, but it can be harder than it sounds.
When the spinnaker is about to start its roll out to windward you should already have the tiller to leeward to counteract this movement, and vice versa. Don’t go too far though as this could result in spinning out the opposite way.
 
 
 
Advise
 
The best advise obviously if you are cruising is to not get into this situation in the first place.  When the wind pressure is climbing, pull in the canvas to a safe level.  No need to heel more than 15'.  My rule of thumb when cruising is if the boat's heel is sustained at 15 to 18', put in the first reef.  This will stand the boat back up and you can power up more.  The boat will be far more comfortable and the mental attrition which is attributed to the higher heel will diminish and you will find out that you will go faster!

 

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